Magmatic degassing

Hilton D. R., Thirlwall M. F., Taylor R. N., Murton B. J., and Nichols A. (2000b) Controls on magmatic degassing along the Reykjanes ridge with implications for the helium paradox. Earth Planet. Sci. Lett. 183, 43-50. 

In the broadest terms, Matuso (1960) recognized that the composition of volcanic gas reflects the balance of contributions from magmatic degassing and from the crust. An oft-quoted sequence of volatile release with decreasing pressure, based largely on experimental observations of solubility in the melt, is... 

Common in high temperature volcanic gases and a good indicator of magmatic degassing. Fluxes readily measured by remote sensing methods. 

In all known cases the starting fluid for a submarine hydrothermal system is predominantly, if not entirely, seawater, which is then modified by processes occurring within the oceanic crust. Four factors have been identified the two most important are (i) phase separation and (ii) water-rock interaction the importance of (iii) biological processes and (iv) magmatic degassing has yet to be established. 

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